Proper operation of a crane dictates that the operator's line of sight to the load as it is lifted, to possible overhead obstructions, and to spotters positioned to direct the operator through hand signals be unimpaired. Such line of sight visibility can be enhanced by elevating the operator relative to the crane, and prior art arrangement have been provided for this purpose. Similarly, tilting the operator rearward can improve visibility overhead, or at least provide comparable visibility with less physical strain on the operator. Prior art arrangements have provided a tilting mechanism.
The present invention provides both elevating and tilting capability, which capabilities are independently controllable, and utilizes a parallelogram linkage to maintain the cab platform level as it is elevated and to move the cab laterally to the side of the crane to reduce the visual obstruction normally resulting from the crane boom. The structural arrangement for the elevating mechanism is also compact permitting the cab, in its lowered position, to be positioned in close proximity to the crane upper works, is relatively simple and inexpensive to manufacture and maintain, and may be readily removed with the cab as a unit to facilitate disassembly of the crane for transport between job sites.